July 13, 191 ij 



NATURE 



65 



in a manual class, say a carpenter's shop, and the first 

 question they ask is, Are you going to make them all 

 carpenters? They do not see that it is not the wood or 

 the tools that are of consequence, but the play of intelli- 

 gent thought that brings them together to produce a certain 

 object which has been already formed in the brain. 

 Those who assist in production should know some- 

 thing of the processes — such as a knowledge of mechanics 

 — the principles upon which an industry depends, 

 and the nature and property of the material they are 

 using ; then the work becomes more interesting, and the 

 proficiency of the worker a matter of concern to himself 

 as well as to his employer, and it is this conviction which 

 has produced our technical schools. The time has surely 

 come when manual training should be available and free 

 to every scholar in our schools, and domestic economy in 

 all its branches to every girl." 



The will of the late Dr. Harry Bolus, of Kenilworth, 

 near Cape Town, contains a munificent provision for scien- 

 tific and educational objects. Dr. Bolus's herbarium and 

 library, the collection of which had been one of the prin- 

 cipal works of his life, are left to the South African 

 College, Cape Town, an institution in which he had 

 previously shown his interest by a large contribution to 

 the foundation of the chair of botany, which is called by 

 his name. He leaves a sum of 20,000/., invested in 

 Government Stock at 4 per cent., on trust for the upkeep 

 and extension of the herbarium and library. This amount 

 will later be increased by an additional sum of 7000/. A 

 further amount of 2i,oooZ. is also left to the same college 

 for the foundation of scholarships. It is directed that in 

 the selection of scholars to benefit under this fund regard 

 shall be paid to necessitous circumstances and proof of 

 industry, and not exclusively to ability. Eventually Dr. 

 Bolus's landed property, on which is situated the house in 

 which he lived and in which he did the greater part of his 

 botanical work, becomes the property of the college, the 

 proceeds to be applied to the purposes previously indicated. 

 This is the largest bequest ever made to an educational 

 institution in South Africa 



SOCIETIES AND ACADEMIES. 



London. 



Royal society, June 29. — Sir Archibald Geikie, K.C.B., 

 president, in the chair. — Francis Darwin and Miss 

 D. F. M. Pertz : A new method of estimating the aper- 

 ture of stomata. The apparatus here described under the 

 name of porometer is similar in principle to that devised 

 in 1873 by N. J. C. Miiller, but differs from it completely 

 in construction. By a simple arrangement a current of 

 air is drawn through the stomata of a living leaf, its 

 velocity being measured by the fall of a water-column. 

 At a constant pressure the rate of air-flow is necessarily 

 dependent on the size of the stomatal pores, and it is 

 accordingly found that agencies such as darkness or loss 

 of water supply, which are known to diminish stomatal 

 aperture, cause a striking drop in the rate of air-flow as 

 recorded by the porometer. In studying the effect of 

 severing the leaf stalk, and thus cutting off the water 

 supply, it has been proved that the first effect of withering 

 is a wide opening of the stomatal pore, confirming 

 F. Darwin in Phil. Trans., B, vol. cxc, 1S9S, p. 548. 

 The porometer has been found of value in attacking the 

 question of the causal relation between stomatal aperture 

 and transpiration. This subject, on which a large number 

 of observations have been made, will be fully treated else- 

 where. In the present paper a single experiment is given 

 illustrating the parallelism between the transpiration rate 

 and the condition of the stomata as revealed by the poro- 

 meter. — S. Chapman : The kinetic theory of a gas 

 constituted of spherically symmetrical molecules. This 

 paper may be regarded as a sequel to Maxwell's kinetic 

 theory of a gas the molecules of which repel one another 

 according to the famous fifth-power law (Phil. Trans., 

 1867). Maxwell's deductions from his hypothesis were 

 found not to agree with fact, but the theory was valuable, 

 because it was the only mathematically rigorous kinetic 

 theory in existence. When he wrote a later paper on the 



XO. 2 1/6, VOL. 8/] 



same subject (.Phil. Trans., 1879) he was aware of the 

 defects of his assumption, but was prevented by certain 

 analytical difficulties from generalising his theory by adopt- 

 ing a wider hypothesis. In this paper these difficulties 

 have been very largely overcome. With the same rigour 

 as in Maxwell's theory, formulas are deduced for the 

 coefficients of viscosity, diffusion, and thermal conductivity 

 in a simple or compound gas. The molecules are assumed 

 to be spherically symmetrical, but no particular kind of 

 interaction is postulated. The latter, however, is involved 

 in the formulas by the occurrence, as factors, of two 

 definite integrals. Certain relations may be deduced with- 

 out the evaluation of these factors. The most interesting 

 of these is d=§fj.C„, where 8 is the thermal conductivity, 

 ix the viscosity, and C„ the specific heat at constant 

 volume. This formula, which was also obtained by Max- 

 well, has always been regarded as a special consequence 

 of his hypothesis, whereas it only depends on the spherical 

 symmetry of the molecules, and is true for rigid-elastic 

 spheres, among other cases. In general, the formulae can 

 be completed only by the evaluation of the before-men- 

 tioned factors. In the paper this is done for the case of 

 rigid-elastic spherical molecules, for centres of force 

 repelling according to the inverse nth power law of 

 distance, and for the case of rigid-elastic spheres 

 surrounded by fields of attractive force. The last case 

 furnishes a rigorous proof of Sutherland's formula for 

 viscosity, and some important corrections to his theory 

 are made. Finally, the formulae obtained are compared 

 with experimental results to test the accuracy of the 

 various laws considered, and to obtain improved data con- 

 cerning the molecules and other physical constants of 

 gases. — Major P. A. MacMahon : Memoir on the theory 

 of the partitions of numbers. Part vi. — Partitions in space 

 of two dimensions, to which is added an adumbration of 

 the theory of partitions in space of three dimensions. In 

 this part the author considers the partitions of a number, 

 the parts being placed at the nodes of an incomplete 

 lattice in two dimensions. Thus, the lattice being of the 

 nature depicted, 



-> 



the parts are in descending order of magnitude in each 

 row and in each column. The enumerating generating 

 function is required. It is found that for a lattice of 

 given specification and a given restriction upon the part 

 magnitude the generating function satisfies a functional 

 equation. From this the functional equation satisfied by 

 the corresponding inner-lattice function, as is defined in 

 part v., is deduced. This investigation then turns upon 

 the determination of the fundamental solutions of this 

 equation and the expression of the generating function by 

 means of them. The complete solution of the problems in 

 hand is thence obtained, and the inner-lattice function is 

 shown to be expressible in an elegant determinant form. 

 At the end of the paper the subject of three-dimensional 

 partitions is broached. It is shown that the method of 

 lattice functions is again available, and the particular case 

 of partition at the summits of a cube is worked out in 

 detail from this point of view. The further investigation 

 of this interesting question is reserved for a future com- 

 munication. — W. T. David : Radiation in explosions of 

 coal gas and air.— Dr. T. E. Stanton : The mechanical 

 viscosity of fluids. The paper deals with the experimental 

 determination of the ratio of the shearing stress to the 

 rate of change of distortion in fluids which are in sinuous 

 or eddying motion. Thus in a fluid in eddying motion 

 flowing through a parallel pipe of circular cross-section, if 

 F is the mean shearing stress on any cylindrical surface 

 of radius r concentric with the pipe, and v the average 

 velocity in the axial direction of the fluid in this surface, 



then writing F = n'-~ the object of the experiments was 



the determination of n' as a function of the dimensions 



